Enhanced efficiency of polyamide membranes by incorporating TiO2-Graphene oxide for water purification

Abstract

Membrane-based separation processes are very effective in several applications such as purification of drinking water and treatment of wastewater. Polymer-inorganic composite reverse osmosis membrane is a powerful method that opens the door to merge different properties of inorganic materials like mechanical and thermal stability with organic polymer properties including processability and flexibility. This work aims to modify aromatic polyamide membrane surfaces by the simultaneous incorporation of graphene oxide (GO) and TiO2 composite, to enhance the salt rejection and filtration performance of the membrane. 1, 3, 5-benzenetricarbonyl chloride, TiO2-GO composite, and m-phenylenediamine were polymerized on the surface of porous polysulfone support. Fourier Transform infra-red spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were applied to confirm the presence of TiO2-GO composite on the membrane surface. Scanning electron microscopy equipped with energy-dispersive X-ray and atomic force microscopy were carried out to analyze the surface morphology and reveal the smoothening of the modified membrane surface. Water contact angle measurements were carried out to visualize the hydrophilicity improvements of modified membranes. The performance parameters of the membrane, including permeate flux, salt rejection, and oil rejection were evaluated using a laboratory setup. The incorporation of TiO2-GO composite into the membrane matrix enhanced the membrane performance with 62 LMH (Lm−2h−1) permeate flux, 97% salt rejection, and 100% hydrocarbons rejection, due to changes in charge, roughness, and hydrophilicity of the membrane surface.